This invention relates to power controls for heat engines, and more particularly to power control devices for double-acting Stirling engines.
The Stirling engine is widely believed by experts in the power field to have good potential for replacing the internal combustion engine in a considerable number of applications. The Stirling engine uses an external combustor which can be adjusted for efficient and clean combustion using a wide variety of fuels, including petroleum and non-petroleum liquids and a variety of solid and gaseous fuels. The engine itself is quiet, efficient, and has a good potential for a long maintenance period. For these reasons, a great deal of effort has been devoted to Stirling engine research and development in the recent past, and rapid improvement in this technology has occurred.
However, one of the areas in which improvements are still needed is in the power control area. The effective power control techniques that have been developed and adopted thus far are complicated, expensive, and unreliable. Moreover, they often impose an engine efficiency penalty at power levels below full power which, in some applications, represent the greatest proportion of use.